Prior-art devices for guiding a power tool along an advancing direction consist of a baseplate that can be fastened to a substrate by a fastening means, and of a guide rail section that can be joined to the baseplate by a joining mechanism and that has a contoured means. The power tool is arranged on the guiding device by means of a guide carriage and can be moved along the guide rail section by means of an advancing mechanism. The guide carriage has a counter-contoured means that can be made to engage with the contoured means.